1. Field of the Invention
The present invention relates to a scan driver for a flat panel display (FPD), and more particularly, to a scan driver that may selectively perform progressive scanning and interlaced scanning.
2. Discussion of the Background
A scan driver is an indispensable circuit for a FPD. The scan driver is used to drive a plurality of pixels that are arranged in rows and columns. In order to drive the pixels, the scan driver enables a selected row of pixels to emit light or enables data to be input to selected pixels.
Generally, formation of one image frame requires a vertical synchronous signal, which defines an image frame display period, and a horizontal synchronous signal, which drives each of a plurality of pixel lines forming the image frame. While the horizontal synchronous signal is activated, image data is input to pixels arranged in a line to which the horizontal synchronous signal is transmitted.
In a passive matrix (PM) display, pixels start to emit light when image data is input; however, in an active matrix (AM) display, after storing input image data, all pixels arranged in one line emit light during a predetermined time duration.
In a liquid crystal display (LCD), an organic electroluminescent (EL) display, and a plasma display panel (PDP), the horizontal synchronous signal is typically referred to as a scan signal. Therefore, a signal that selects and activates lines will hereinafter be referred to as a scan signal.
A circuit that transmits the scan signal to a panel in which pixels are arranged is a scan driver. More specifically, the scan driver transmits the scan signal to respective lines of the panel. The selection and activation of lines via transmission of the scan signal may be performed according to a progressive scan method or an interlaced scan method.
In the progressive scan method, a scan signal is sequentially transmitted to the panel lines. That is, the scan signal is sequentially transmitted to each of a first line through a final line.
In the interlaced scan method, a frame is displayed through two processes. Specifically, in a first process, a scan signal is sequentially transmitted to odd-numbered lines during an odd field period corresponding to half of a frame period. In a second process, a scan signal is sequentially transmitted to even-numbered lines during an even field period corresponding to the remaining half of the frame period.
Accordingly, a conventional FPD utilizes either progressive scanning or interlaced scanning to display image data because the FPD does not include a scan driver that can selectively perform progressive scanning and interlaced scanning.